Utility lines, such as lines for telephones, electricity distribution, natural gas, cable television, fiber optics, Internet, traffic lights, street lights, storm drains, water mains, and wastewater pipes, are often located underground. Utility lines are referred to as “buried assets” herein. Consequently, before excavation occurs in an area, especially an urban area, an excavator is typically required to clear excavation activities with the proper authorities and service providers. The clearance procedure usually requires that the excavator contact a central authority (such as “One Call”, “811” and “Call Before You Dig,” which are well known in the art) which, in turn, sends a notification to the appropriate utility companies. Subsequently, each utility company must perform a buried asset detection procedure, which includes having a field technician visit the proposed excavation site, detecting the relevant buried assets and physically marking the position of the buried asset using temporary paint or flags. Usually, a technician visiting a proposed excavation site utilizes a device known as a conventional locator—a commercial, off-the-shelf, utility locator device that detects and identifies buried assets using radio frequency and/or magnetic sensors. Upon completion of this procedure by the appropriate utility companies, excavation can occur with the security that buried assets will not be damaged.
Utility companies are faced with increasing requests to locate and mark the position of their buried assets to avoid damage from third party excavators, contractors and underground horizontal boring operations. One of the main obstacles experienced by locate technicians involves the presence of multiple buried assets in close proximity A single buried asset carrying a suitably impressed signal emanates an electromagnetic field in a standard circular radiating pattern 510 shown in FIG. 5A. Conventional pipe and cable locator devices 530 perform well when encountering a single buried asset radiating the standard circular electromagnetic signal pattern 510 from under the ground 518. When multiple buried assets are present in close proximity, however, interference signals are likely to result like pattern 520 shown in FIG. 5A. Conventional locator devices do not perform well when encountering multiple buried assets emanating the interference signals such as the pattern 520. Interference signals such as shown in 520 require the services of a very experienced and skilled technician to detect such a situation exists and it is very time consuming to make the appropriate adjustments so as not to mis-locate the buried asset the technician is seeking. With experienced technicians in short supply, utility and locator companies do not have the resources to attend to all such situations that are presented. Even for experienced and skilled technicians, finding a target buried asset when interference signals are encountered can be time-consuming or simply not possible, and can lead to errors and mis-locates. As such, this leads to increased costs for utility companies and service providers, as well as potential safety hazards to workers and the general public.
Therefore, a need exists for improvements over the prior art, and more particularly for more efficient methods and systems for detecting and locating multiple buried assets in close proximity